Natural intraocular lenses in the human eye lose its vision due to the build up problem on the surface of the lenses or damage of lenses by aging and/or diseases passed. Today, the build up problem on natural lenses replaced with the new synthetic lenses by an operation known as cataract surgery. Domestic natural eye lens in the human eye has been first replaced in 1949 using methyl methacrylate-based hard polymeric lens. In general, different acrylate lenses are used for this aim.
In recent years, surgeons prefer to use lenses with high reactive index, biocompatible, foldable intraocular lenses providing ease on micro incisional surgery.
Intraocular lens manufacturing technology is generally based on thermal polymerization method using a mold and forming it into the lens by turning machine coupled with laser technology. However, this method is time consuming and expensive and has dimensional stability problems due to the production method used. Moreover, invisible fractures can be encountered on the lens of the surface causing so-called glistening problems due to the use of turning processes.
Another manufacturing method for the production of intraocular lenses is the photopolymerization process which is an environmentally friendly and energy saving method. Said method is an appropriate method in terms of production costs. In the prior United States patent document No. U.S. Pat. No. 6,201,036 it is mentioned that an intraocular lens production obtained by the use of photopolymerization method.
In recent years, blue light (400-500 nm) were determined to pose a potential hazard to the retina. In the United States patent document No. U.S. Pat. No. 6,353,069 the production of lenses with high refractive index using two or more acrylate and/or methacrylate-containing copolymers in aromatic structure was mentioned. In the United State patent document of. No. U.S. Pat. No. 5,470,932 the addition of yellow paint into the formulation was mentioned. However, such nonreactive input like acrylate causes diffusion problems causing reduction of the activity of the ingredient by time.
UV (ultraviolet) blocking process as mentioned in Japanese Patent JP10282302 and European Patent No. EP1785747 and WO97/27223 can also be obtained by surface coating of the lenses. However, the desired results cannot be obtained in case of nonhomogeneous coatings. Lenses with non-blocking feature in the range of 300-430 nm may cause second cataract formation and cause negative results from the biocompatibility tests which is the indication of the long-term use results of the lenses.
“The AcrySof Natural Lens SN60AT” yellow lens produced by ALCON company has UV-blocking feature in the spectral transmittance values of 400-475 nm. It was believed and also observed during the eye transplantation operations that especially after 54 years old, natural lens are yellowing in order to reduce the damage of light in the 400-475 nm on retina. The body naturally adjusts itself to protect damage of light on this wave length. Researchers working on cataract surgery believed that this property should also be carried to the synthetic lenses for the patients at the age of 54 or older. ALCON company used ingredients that can absorb blue light and “AcrySof Natural” took commercial product on the market. In order to minimize the diffusion of the blue light absorbing ingredient from the lens ALCON added acrylic groups to the blue light absorbing ingredient as mentioned in the U.S. Pat. Nos. 5,470,932, 7,803,359 and US20100113641 numbered United States patent. All of the aforementioned lenses were obtained by molding thermally and shaping with turning coupled with laser.
United States patent No. US20120232648 mentioned lenses with a shape memory polymer (SMP) intraocular lens may have a refractive index above 1.45, a Tg between 10° C. and 60° C., inclusive, de minimis or an absence of glistening, and substantially 100% transmissivity of light in the visible spectrum. The intraocular lens is then rolled at a temperature above Tg of the SMP material. The intraocular device is radially compressed within a die to a diameter of less than or equal to 1.8 mm while maintaining the temperature above Tg. The compressed intraocular lens device may be inserted through an incision less than 2 mm wide in a cornea or sclera or other anatomical structure. The lens can be inserted into the capsular bag, the ciliary sulcus, or other cavity through the incision. The SMP can substantially achieve refractive index values of greater than or equal to 1.45.
In the United States patent document No. US20130107201, a multifocal ophthalmic device is disclosed, wherein the lens body comprises a curcuminoid compound as a UV-light stabilizer and/or co-polymeric composition which is drawn from pre-polymerization mixture of defined monomers lens body of the multifocal ophthalmic device is being formed. With a plurality of concentric annular Zones, which effect both diffraction and refraction of incident light, and which separated by slanted steps that are substantially devoid of any diffractive or refractive power.